Soap manufacture



Patented Aug. 30, 1949 2;480,564 v scin- MANUFACZI URE William E; "Forney, ltierchantville; N. 2L,- ass'ig'nor to Cities- Se'rvicefiil Comalny,-' New 'Yo'rlg-N. Y fa'c'orporation of Pennsylvania 'No' Drawing. lipplicationfJune'z'i, 1946, Serial No. 679,858

tideso'f various kinds and carbon content, to-

get-her with small amounts 1 of unreacted starting material. While the whole mixture may bejc'a'sionally be'used'without further refinement, it is generally-desirable to separate it into one-or "more fractions having special utility in 'them- *selvesor as the' s'tarti'ng materialsfor the preparation ofoth'er products.

'The conventional method of stripping 'the hydroxy acids "from mixtures of this kind preparacosy, for example, tothe formation of oil soluble '-'s'oaps-'o'f the 'r'esi'dualcarboxylic acidfraction, involves the treatment of the Wax acids with as much as ten volumes of naphthaygivingjris'e to the separation odtfof a small amount'of' insoluble hydroxy 1 acidmaterial, and of then "precipitating naphtha=soluble hydroxy acids "by treat ng the solution with -ortho phosphoric acid. *I-he fly"- "droxy-aeid-fre'e oxidation "products 'reccver'eu from the naphtha solution foliowing this treat Ln-rent are essentially carbox'ylic aeiaswcgemer with alcoholspaldehyde's, 'ketons, =e tc.- whih' in'ay "be converted to 1 salts by'reaction' with ='a selected 'metalox-ifie'or 'hydroxide; I V

The foregoing process is objectionable 5mm the'sta'n'd point of thelo'ng time'which'i required to effect substantially complete precipitation 61? the hydroxy' acidsirom the naphtha solution. 'Thus 'the solution must be treat-edrepeatedly with small volumes of ortho phosphoric acid; and be left to stand for a'p'erio'd-of faboiit 'two hours btween each-acid dump for the settling-onto the very "fine rec'i 'i-tate' which is *forined; In actual practice, for example, the treatment 'isju'suallfy repeated four or'f'five times in "order "to died 1 an adequate separation :of "the precipi'tatapre matt'er'. A further objection to. .this'proces's arises from the diff culty andnexpense whijch'is attendant upon the recoverypf the phosphoricacide-a step which must be takemhowever, i-f=. the ,process.is

(to be carried out on-.a commerc ial-scale. p r

Further problems arise -.in-, they ipreparation, :of soaps of the 'wax' acids which are :recovered :in itheiforiegoing or \in-.an"ytoth'e'riway; This is riparzticulaflyso when thesegorzinzfacl; ifatty acids oi .2 Claims. (01. 260 414) s 2 a lt'ifid are-to'be 'convertedto soaps by-the conventional double decomposition process involving saponi'fication with sodium hydroxideior example, and the subsequent reactionof the sodium --s'oap which 'is thus formed with the compound 61" the 's'el-ecte'd=meta1 toyield'a final-desired prod-- not. The diificulties which are encountered in the -wa-'shiu'g of the water insoluble finalsoap to remove all traces of-sodium salts, "etc and the losses which are occasioned by the form'ation of er'nulsieh-s in the course of this tedious washing operation, are so familiar to those skilledin the art ashardly t'o require-detailinghere 1 The principalobje'ct oitheinvention is'to pr'o videadouble 'de'(fornposit-ion"method for the :preparation of a soap o'fa selectedm'et'al 'andan organic acid-derived -from wax, natural fats, oils "brother sources'gwhich is'easier to carry=out,' less con's'l'i'mii'i of expensive chemicals, and results in a snraner loss of reaction products than the "methods which are conventionally employed in rnakihg products of this kind.

It is a further object'of theinvention to provide a 'rnethod-forforming an oil soluble soap of a se-lected fraction of crude wax acids which avoids -the' trouble's incident to the refining iof crude wax acids by phosphoric acid'precipitation,

as well as those which arise in the conversion or thewax acids to the 'final metal salt'by'd'o'ubl'e decomposition as conventionally practiced in the prior art.

"Other objects, and various features "will be brought out in the following description of my :n'ewzpr'ocess as illustrated by several specific'eio- --'amp1e's.

In the appl-ioationpf'the invention to'the preparation emu oil soluble wax acids soap,ia'-crude mifitu' re 0f oxidation products obtained by the controlled air blowing of paraffin or other Waxy v'inaterial i's first refined to'eliminate substantially :all of the :'hydroxy acid constituents, leaving a "'fractionconsisting 'essentiallyof 'carbo'xylic acids and esters for conversion into oi1'soluble"soap of thei desired' kind. In! preparing such 'a' carboxylic acids fraction by my:method,;a suitablebatch'o'f crude wax acid is first cut with at least four volumes of naphtha to give a solution from which the hyaroxy acid fraction'inay be precipitated by "contact with" concentrated sulphur-ic-acidranging fro'mabout 75 per centstreng'th up'to fuming grade. Thus, :e'xcellent'results may be obtained byadding 66 B.su1phuric acid to such a solutic'h 'in'ah aniountrepresentin'g from 4't0 IO percent by weight of the-dissolved crude wax 'acidsfa'nd lby stirring this: mixture-for a-period otfrom 5 th 3 minutes to assure adequate contact between the inorganic acid and the dissolved wax acids.

Upon completion of this treatment, the mixture should be permitted to stand for a period of time sufiicient to permit it to settle into two welldefined layers. The lower of these layers consists essentially of hydroxy acids accompanied by some alcohols, aldehydes and ketones, together with substantially all of the sulphuric acid which was added as a precipitant. This layer may therefore be drawn off into 3-4 volumes of water to dilute the sulphuric acid to the point where it will separate out and leave a mixture of the hydroxy acids, and possibly some naphtha, for further refinement and treatment in any suitable way.

The clear naphtha solution which remains after the drawing oil of the sulphuric acid-hydroxy acids contains the balance of the crude oxidation products in the form of hydroxy-free acids and esters as major ingredients, together with a small percentage of alcohols, aldehydes, ketones and possibly lactones and lactides, this mixture, for

want of a better term, being referred to as the carboxylic acids fraction. It will be evident that the foregoing steps deal only with initial separation of the crude oxidation products, and the preparation of a fraction which is suitable for conversion into metal soaps of a desired character. In accordance with my invention, this conversion is efiected by double decomposition in which the naphtha solution is first treated with ammonia, in dry or aqueous form, in such quantity as to convert the organic acids and ester constituents into ammonium soaps, and in which those soaps are then reacted with a compound of a selected metal to displace the ammonia and yield the desired metal soap as a final product.

It is of note that the foregoing reaction is carried out at a temperature which is high enough to drive off all of the ammonia, along with such water as may be present, the ammonia being recovered for reuse. Upon its completion, the naphtha may readily be flashed off and recovered, thus leaving a mixture of metal soaps oi the carboxylic acids fraction of the original crude wax oxidation products, together with unreacted alcohols, aldehydes, ketones and oxidation products. The product which is so recovered will obviously be free of ammonia, and accordingly requires no washing or other supplementary treatment to prepare it for immediate use.

The complete process of extracting a carboxylic acids fraction of crude oxidation products and conversion of that fraction to metal soap in the foregoing manner is obviously more expeditious, less troublesome, and very much more economical than prior art methods of accomplishing the same results. It is of particular note, however, that the soap making phase of the invention is not limited to use in the treating of a particular wax acids fraction. On the contrary, it appears to be one of general application to the preparation of soaps from natural fats and oils, and is particularly useful in the preparation of heavy metal soaps of "fatty acids from any source.

Example I of this reaction substantially all of the hydrocarbons were oxidized to a greater or lesser extent, giving a final product which consisted essentially kind.

4 of organic acids, aldehydes, esters, ketones, lac tones, and lactides, together with a small percentage of unreacted wax. This particular mixture proved to have a neutralization number of about 67 with a saponification number of approximately 130.

In carrying out my process, a gram sample of the foregoing crude wax acids was treated with 400 cc. of Pennsylvania straight run naphtha having a boiling range of -250" F., i. e., in a ratio of about one volume of oxidation products to four volumes of naphtha. From a practical point of view, this seems to represent about the lowest ratio of wax acids to solvent which can be successfully employed. The crude wax acids may, however, be cut to a very much greater extent than I have indicated, and if the dilution is carried far enough, say to a ratio of about 1:10, some hydroxy acids may be precipitated out in this step. The amount of hydroxy material which can be separated out in this way is usually so small as hardly to warrant the added cost of handling the larger volume of solution throughout the process, and particularly of flashing off and recovering the extra naphtha in its final stage. In general, therefore, I prefer to use the minimum amount of naphtha which will yield a solution from which the hydroxy acid fraction may be precipitated by contact with concentrated sulphuric acid, and thus to gain the advantage of the smaller volume of liquid to be handled in the process.

In order to precipitate the hydroxy acid materials from the foregoing solution, I added 4 cc. of concentrated sulphuric acid (66 Be.) representing approximately seven per cent of the weight of the original wax acids sample. It is essential to the successful carrying out of this step that good contact be established between the sulphuric acid and the entire naphtha solution, a result which was accomplished by a thorough stirring of the mixture for a period of about twenty minutes.

At the conclusion of the acid treatment, the solution was allowed to stand for a period of time sufficient to permit the settling out of the precipitated oxidation products along with the added inorganic acid. In the instant case, about two hours of standing sufiiced to establish two clearly defined layers of which the lower was drawn off for the recovery of both the sulphuric acid and oxidation product constituents. Such a recovery was readily efiected by diluting the precipitate with about three volumes of water and by heating the resulting mixture to a temperature of from -200 F. with vigorous stirring preparatory to settling out the dilute sulphuric acid. Upon the drawing off of the latter, the remaining greenish-amber colored oil layer was washed again with water to eliminate any traces of sulphuric acid, thus giving a product representing about 23 per cent (by weight) of the original wax acids, and consisting primarily of hydroxy acids and secondarily of alcohols, esters, ketones and other oxidation products in such a condition that they may readily be refined'or further treated in any suitable manner.

It will be evident therefore that the foregoing steps deal only with the preparation of what I call carboxylic acids fraction of the crude wax acids, for conversion into metal salts of a desired These hydroXy-acid free oxidation products, as retained in the clear naphtha solution following the drawing off of the precipitate in the foregoing manner, may be further refined in vZprml'uctrecovered from the final any suitable way to increase the concentration the-final product is desirable. The whole naphtha suiutionwas accordingly transferred toa-fla's-k fitted witha reflux condenser whereI added approximately 50 cc. o f concentrated ammonium hydroxide, this" quantity representing that theoretically required for saponification of the organie acids and esters, plusabout per cent excess. The resulting solution was heated toass-ist-ilrtl-ie saponification, which started when the temperature had reached about 150- F.-, and was completed at a temperature of from 175-185" F. after a reaction period of about twohours order to convert the ammonium salts of the foregoing reaction to magnesium soaps for use as oil addition agents, I added a water slurry con-- taining ten grams of magnesium oxide tothe naphtha-soap solution, and continued refluxing for a period of about three hours at a final te1nperature or around 220 F. The ammonia which wasdispl aced in this reaction was driven off with water, andwas recovered as ammonium hydrox= ide for reuse in the process. At the end of this replacement reaction, the naptha solution was permitted to" stand for the settling out of excess magnesium oxide, the clear solution then filtered, and the naptha flashed off and recovered, leaving a mixture of magnesium soaps along with unreacted alcohols, aldehydes, ketones and other nonsaponifiable matter.

The reactionproduct which was so recovered represented about '77 per centof the weight of .theoriginal wax acids sample of whichBO per cent was magnesium soap (based upon assumed average molecular weight of 220 for the acids invalved) containing about 2.0-2 per cent'by weight of'magnesium. It is of particular note that this product was uncontaminated by ammonia or its compounds, and required no water washing or other after treatment to prepare it for ultimate Iuse.

The results of a repetition of the process upon briefly above, in terms of the magnesium reaction n'aptha solution,

are tabulated below Magnesium Magnesium O t d Reaction Soap f all-1e sample Product, Content, zg s g grws (Per Gent)- e a 74 31. 9 2. 23 b 75 30.9 2 14 c 75 34. 8 40 The: quantity of hydroxy acid material which maybe separated out in any given case, as well as the yield of final metalreaction product, will of course depend upon the nature of the wax acids under treatment; that is to say, upon the character of the hydrocarbon which has been subjected to oxidation, the length of oxidation treatment and the pressure, temperature and other process factors employed, all as is well understood in the art. This was demonstrated by a repetition of my process, in both its separatory 6'. and soap-forming steps, upon tour difierent ples of crude wax acids which were-obtained by blowing molten paraflzi-n with air for-increas ingly long periods oftime. In each case amt) each case are tabulated'below:

SampleNo 1. 2' i 3.1

Neutralization No Saponification No Sulphuricacid. (66 B.) Hydroxy-acids Mg. Rea'ctionlrcduet. Contained Magnesium ..per cent Example II The soap making steps of my method are fnily applicable to the treating of wax acids fractions prepared in other waysthan, the preferred. one which has. just been described. By way of illusitration, a sample of the: crude oxidation products referred to Example: I waseu't: withnaphtha in a ratio of about 1:10 by volume; iand the hydroxyr acid constituents were then precipitated outbytreatment withphosphoric acid. accordance with well understood prior art practices. The carbcxyllc acid fraction which was: sepae rated out in this fashion represented about 69 per cent (by weight) of. the crude productiunder treatment. A 50-gra-m sample of this product, dissolved in about 400 cc; of straight-runnaphtha (-250) was placedin a flaskfittedwithia reflux condenser alongwith; 25: cc: of concentrated ammonium hydroxide solution, and the mixture was heated at reflux temperature-fora period of about two hours, to convert the; acid and ester constituents of thesoluti'on to: ammoni um salts. At the end of that period; a slurry of: 5 grams finely groundmagnesium oxide in about 15 cc. of water, was added to the flask andiheating was continued for an additional two hour period at reflux temperature. During the course? of the reaction of the magnesium oxide and am:- mon-ium salts, naphtha was taken off overhead so that'the boiling point. ofthe. mixture gradually rose to about 2l0-2 1'5-'F'. with ajconsequent driving off of both ammonia and water. When it appeared that all the water had beenv eliminated, the mixture was cooled, allowed to settle and-then clarified by filtration.

Upon the conclusion of the foregoing. the

Example Hf Thenew' soap making method has; also been applied with complete success to'the treatment of naturally occurring oils and fats of both animal and vegetable origin. In one case, for example, soya bean oil was treated with concentrated ammonium hydroxide to yield an ammonium soap for subsequent reaction with a metal compound. This saponification reaction does not proceed readily at atmospheric pressures, butmay easily be carried out at a pressure such as to hold the ammonia in contact with the oil. In the instant case, the natural oil and ammonium hydroxide were reacted under the autogenous pressure generated by heating these ingredients in a closed bomb at a temperature of about212 F. The ammonia soap product thus formed, was then dissolved in naphtha, and a slurry of magnesium oxide in water was added to the solution for the purposeof displacing the ammonia and forming a magnesium soap, this reaction bein carried out under reflux conditions with continuous take-off of light naphtha fractions so that the temperature rose gradually to about 215 F., with a consequent driving ofi of both the ammonia and water. When it appeared that all of the water had been displaced, the solution was settled and filtered and the naphtha was then distilled off, leaving magnesium soap as the principal product.

The glycerine which was formed in the saponification reaction may be removed at the completion of that step or later, as may be most expedient. In the instant case, it was extracted with water after the completion of the soap mak- I,

ing operation, thus yielding a final soap containing 6.36 per cent by weight of magnesium. It will be evident that this metal content is somewhat in excess of its theoretical content of about 4 per cent, the difierence being accounted for by the presence of a molecule of combined MgO.

The natural acid and ester constituents of a lard oil have also been converted to magnesium soap by following precisely the technique described above. out with concentrated ammonium hydroxide under the autogenous pressure developed in the course of heating this mixture in a closed bomb at a temperature of about 212 F., and by reacting the resulting ammonium soaps, in naphtha solution, with magnesium oxide. The soap which was recovered upon the driving oil of naphtha and extraction of its glycerine content, was found to contain 6.65 per cent by weight of magnesium,

this again being in excess of the theoretical meta1 content of the finished product and apparent- 1y attributable to the presence of a molecule of combined MgO.

It is of note that both the soya bean and lard oils were reacted with ammonium hydroxide in the absence of any intervening solvents because of space limitations of the particular bomb which was available. In general, it appears that the reaction proceeds more easily and readily when the oils are first dissolved in naphtha, and the ammonium soap product is then recovered in the liquid form which may be handled most easily in the final stages of the process. We prefer therefore to cut the oils with naphtha in suitable ratio, and to treat the resulting solution with ammonium hydroxide or dry ammonia gas, and then to carry out the metal replacement step just as heretofore described.

It will be observed that the foregoing specific examples deal only with the preparation of mag nesium soaps of various organic acids and esters. In other instances, and by following precisely the general method which has been described, I have reacted copper and calcium compounds with the ammonia soaps to yield final soaps of those Thus saponification was carried metals, and various tests indicate that the method is fully applicable to the preparation of lead, silver, cobalt and aluminum soaps, and seemingly soaps of any selected metal. Insofar as the character of the metal compound is concerned, I prefer to use the oxides and hydroxides of the selected metal, and in appropriate cases, the carbonates and chlorides, to form ammonium reaction products which readily break down upon heating so that both the ammonia and other constituents will separate from the finished metal soap and pass off with the eiiluent vapor, thus avoiding the necessity of washing the finished metal soap or subjecting it to other after treatment.

It is of further note that the invention is not limited to the preparation of soaps of the specific fatty acids and esters which have been considered in the several examples. On the contrary, as those familiar with the art will recognize,-fatty acids and esters may be prepared from various paraifinic and naphthenic petroleum fractions, as well as from animal and vegetable products, and are all suitable for conversion to soaps in the foregoing manner.

Having described my invention in its broadest aspects and illustrated it by way of specific examples, what I claim as new and useful is:

1. The process of making an oil soluble soap of wax acids which comprises the steps of treating a naphtha solution of substantially hydroxyacid-iree oxidized petroleum wax with ammonia in such quantity as to convert its organic acidester constituents to ammonium salts, reacting such salts in naphtha, solution with'magnesium oxide to convert them to magnesium soaps, said reaction being carried out at a temperature such as to drive off the displaced ammonia and water, and separating the magnesium soaps from the naphtha solution.

2. The process of making a metal soap, which comprises the steps of dissolving substantially hydroxy-acid-free oxidized petroleum wax containing acidic components in naphtha, treating such solution with ammonia to form ammonium soaps of the acidic components of such material,

reacting such ammonium soaps in naphtha solution with a metal compound selected from the group consisting of the oxides and hydroxides of magnesium, calcium, and copper to convert them to metal soaps, heating the resulting mixture at a temperature such as to break down and drive oil ammonia compounds which are formed in the last-mentioned reaction, and recovering the metal soaps from the naphtha solution.

WILLIAM E. FORNEY.

REFERENCES CITED The following references are of record in the CO 'file of this patent:

UNITED STATES PATENTS 

